// check the type of birthday and its constructor
let birthday = new Date("1990-01-01");
console.log(typeof birthday);
console.log(birthday.constructor);
console.log(birthday);
// check the type of array and function
console.log(Object.prototype.toString.call(birthday) === "[object Date]"); // true
console.log(Object.prototype.toString.call([1, 2, 3]) === "[object Array]"); // true
console.log(
  Object.prototype.toString.call(function () {}) === "[object Function]"
); // true

console.log(new Date().getTime());
console.log(new Date().toLocaleDateString());
